TY - JOUR AU - Zhang, Yuezhou AU - Folarin, Amos A AU - Sun, Shaoxiong AU - Cummins, Nicholas AU - Vairavan, Srinivasan AU - Bendayan, Rebecca AU - Ranjan, Yatharth AU - Rashid, Zulqarnain AU - Conde, Pauline AU - Stewart, Callum AU - Laiou, Petroula AU - Sankesara, Heet AU - Matcham, Faith AU - White, Katie M AU - Oetzmann, Carolin AU - Ivan, Alina AU - Lamers, Femke AU - Siddi, Sara AU - Vilella, Elisabet AU - Simblett, Sara AU - Rintala, Aki AU - Bruce, Stuart AU - Mohr, David C AU - Myin-Germeys, Inez AU - Wykes, Til AU - Haro, Josep Maria AU - Penninx, Brenda WJH AU - Narayan, Vaibhav A AU - Annas, Peter AU - Hotopf, Matthew AU - Dobson, Richard JB PY - 2022 DA - 2022/3/11 TI - Longitudinal Relationships Between Depressive Symptom Severity and Phone-Measured Mobility: Dynamic Structural Equation Modeling Study JO - JMIR Ment Health SP - e34898 VL - 9 IS - 3 KW - depression KW - mobile health KW - location data KW - mobility KW - dynamic structural equation modeling KW - mHealth KW - mental health KW - medical informatics KW - modeling AB - Background: The mobility of an individual measured by phone-collected location data has been found to be associated with depression; however, the longitudinal relationships (the temporal direction of relationships) between depressive symptom severity and phone-measured mobility have yet to be fully explored. Objective: We aimed to explore the relationships and the direction of the relationships between depressive symptom severity and phone-measured mobility over time. Methods: Data used in this paper came from a major EU program, called the Remote Assessment of Disease and Relapse–Major Depressive Disorder, which was conducted in 3 European countries. Depressive symptom severity was measured with the 8-item Patient Health Questionnaire (PHQ-8) through mobile phones every 2 weeks. Participants’ location data were recorded by GPS and network sensors in mobile phones every 10 minutes, and 11 mobility features were extracted from location data for the 2 weeks prior to the PHQ-8 assessment. Dynamic structural equation modeling was used to explore the longitudinal relationships between depressive symptom severity and phone-measured mobility. Results: This study included 2341 PHQ-8 records and corresponding phone-collected location data from 290 participants (age: median 50.0 IQR 34.0, 59.0) years; of whom 215 (74.1%) were female, and 149 (51.4%) were employed. Significant negative correlations were found between depressive symptom severity and phone-measured mobility, and these correlations were more significant at the within-individual level than the between-individual level. For the direction of relationships over time, Homestay (time at home) (φ=0.09, P=.01), Location Entropy (time distribution on different locations) (φ=−0.04, P=.02), and Residential Location Count (reflecting traveling) (φ=0.05, P=.02) were significantly correlated with the subsequent changes in the PHQ-8 score, while changes in the PHQ-8 score significantly affected (φ=−0.07, P<.001) the subsequent periodicity of mobility. Conclusions: Several phone-derived mobility features have the potential to predict future depression, which may provide support for future clinical applications, relapse prevention, and remote mental health monitoring practices in real-world settings. SN - 2368-7959 UR - https://mental.jmir.org/2022/3/e34898 UR - https://doi.org/10.2196/34898 UR - http://www.ncbi.nlm.nih.gov/pubmed/35275087 DO - 10.2196/34898 ID - info:doi/10.2196/34898 ER -